The signals – if that is what they are – would have been sent thousands of years ago by an advanced civilisation to other solar systems that might support life, Ermanno Borra, of Laval University in Quebec, said.
The theory has been greeted with scepticism by fellow astronomers. However, the research program Breakthrough Listen, whose board includes Stephen Hawking and Mark Zuckerberg, the Facebook founder, has directed a telescope at some of the stars noted by the astronomers in their paper.
Dr Borra, who specialises in new forms of telescopes, published a paper in 2012 speculating on how aliens might use pulses to broadcast coded messages, or even pictures of themselves, to distant galaxies.
In the new paper, published with Eric Trottier, a graduate student, Dr Borra describes identifying similar pulses of light layered over the beams from 234 stars, among 2.5 million recorded by the Sloan Digital Sky Survey, which has been mapping the sky since 2000.
After ruling out natural causes for this phenomenon, or errors in the way they analysed the data, the scientists considered the possibility that they were the product of extra-terrestrial intelligence.
They said that all the pulses originated from sites close to stars similar to the Sun that would be “more likely to have planets capable of having extraterrestrial intelligence”.
The pulses all seem to be broadcasting “with the same time separation”, they write. This could be to distinguish the signals from the background noise of space.
Dr Borra said yesterday that he suspected that different civilisations, spanning 234 stars, could be communicating with each other. He admitted, however, that he was not 100 per cent sure.
Breakthrough Research said that the pulses could have been caused by the instruments used to detect them. It categorised the paper as either negligible or insignificant but added: “If the signal were to be confirmed with another independent telescope, its significance would rise.”
Peter Plavchan, a professor at the Missouri State University in Springfield, who has spent his career looking for planets similar to Earth, agreed with this critique.
“In their paper they were very confident that they had ruled everything else out,” he said. “I don’t think that they had.”